CS235073B2 - Method of heavy hydrocarbons fraction hydrogenation treatment containing metals,asphaltenes,sulphur and nitrogen compounds - Google Patents

Description

The invention relates to the catalytic treatment of heavy hydrocarbon fractions containing asphaltenes, metals, nitrogen compounds and sulfur compounds in the presence of hydrogen.

It is known that crude organics and other heavy petroleum hydrocarbon fractions, such as petroleum hydrocarbon residues, hydrocarbon fractions derived from petroleum sands and hydrocarbon fractions derived from coal, contain various organometallic compounds and asphaltenes, the metals most commonly found in such The hydrocarbon fractions are nickel, vanadium and iron. Such metals have a detrimental effect on various petroleum refining processes such as hydrogenation cracking, hydrogenation desulfurization and catalytic cracking. These metals and asphaltenes clog the gap between the catalyst grains and thereby reduce its useful life. Various metal deposits on the catalyst may act as catalyst poisons or deactivate the catalyst.

In addition, asphaltenes tend to reduce the ability of hydrocarbons to desulfurize. When a catalyst, such as a desulfurization catalyst or cracking catalyst, is exposed to a hydrocarbon fraction containing metals and asphaltenes, the catalyst is rapidly deactivated and must be prematurely removed from the reactor and replaced with a new one.

Although known processes for the hydrotreating of heavy hydrocarbon fractions, including, but not limited to, heavy crude oils, reduced crude oils and petroleum residues, the use of fixed bed catalytic processes is not quite common to convert such raw materials without significant asphaltene deposition. and clogging the reactor while effectively removing metals and other impurities such as sulfur and nitrogen compounds. While it was previously possible to use heavy proportions of hydrocarbons as fuels of lower quality or as sources of asphalt, today's policy and economic conditions require that such material be hydrotreated in order to eliminate the harmful environmental impact of such material and to recover from such higher proportion of usable products.

It is well known that petroleum hydrocarbon fractions can be hydrotreated (i.e., hydrogenated desulfurized, hydrotreated denitrified and / or hydrotreated in the presence of), a catalyst comprising a hydrogenation component and a suitable carrier such as alumina or a mixture of alumina and silica .

The catalyst hydrogenation component comprises at least one Group VI and / or VIII metal of the Periodic Table of the Elements, as listed on page 628 of the Webster's Seventh New Collegiate Dictionary, G. & C. Merriam Company, Springfield, Massachusetts, USA (1963). .

Combinations of metals such as cobalt and molybdenum, nickel and molybdenum, cobal, nickel and molybdenum and nickel and tungsten have proven useful. For example, U.S. Pat. No. 3,340,180 discloses that heavy hydrocarbon fractions containing sulfur, asphaltene, and metals may be hydrogenated in the presence of a catalyst comprising said combination of metals and activated alumina with less less than 5% of its pore volume consisting of pores with a radius of up to 300 xx 10 * ¹⁰ m (30 nm) consisting of pores with a radius greater than 100 x 10 ¹⁰ m (10 nm) and less than 10% of its pore volume consisting of radius greater than 80 x 10 ^"10 m (8 NMJ.

U.S. Pat. No. 4,016,067 discloses that heavy hydrocarbon fractions may be deprived of metals and sulfur on a two-component catalyst system wherein the first catalyst comprises a Group VI metal and a Group VIII metal, preferably molybdenum and cobalt, in conjunction with alumina as a a carrier comprising a significant proportion Å and / or Θ-alumina, wherein at least 60 ° / o of its pore volume consists of pores having a diameter in the range of 100 x 10 ^"10 m (10 nm] to 200 10 ^-10 m χ ( 20 nm) and at least 5% of its pore volume consists of pores with a diameter greater than 500 x 10 ^-10 m (50 nm) and having a specific surface area of up to about 110 m ² / g, and whose second catalyst component comprises a similar hydrogenation component in connection to a refractory support, preferably alumina, in which at least 50%, preferably at least 60% of the pore volume is formed by pores having a diameter in the range of 30 x ¹⁰ cm (3 nm) to 100 ^cm 10 ' ^ιθ m (10 nm) and having a specific surface area of at least 150 m ² / g.

U.S. Pat. No. 2,890,162 discloses catalysts which contain active catalyst components on alumina and have a most common pore diameter in the range of 60 x 10; ¹⁰ m (6 nm) to 400 xx 10 " ¹⁰ m (40 nm) and may have pores greater than 1000 x 10" ¹⁰ m (100 nm), are suitable for desulphurisation, hydrotreating, hydrotreating of naphtha, for isomerization of paraffins, etc., for hydrogenation, dehydrogenation and various types of hydrofining and for hydrocracking of residues and other coatings containing asphalt It is recommended that suitable active ingredients and promoters contain a metal or a catalytic compound of various metals, among which 35 and chrome.

United Kingdom Patent No. 1,051,341 describes a process for the hydrogenated dealkylation of certain aromatics using a catalyst consisting of Group VI oxides or sulfides deposited on aluminum oxide having a porosity in the range of 0.5 ml / g to 1.8 ml / g and a specific surface in the range of 138 m ² / / g to 200 m ² / g, in which at least 85% of the total pore volume is pore, with a diameter in the range of 150 x 10 ¹⁰ m (15 nm) up to 550 χ 10 ¹⁰ m (55 nm).

U.S. Patents 3,245,919 and 3,267,025 disclose processes for converting hydrocarbons such as reforming, hydrocracking, hydrogenation desulfuration, isomerization, hydrogenation, and dehydrogenation using a catalyst comprising a catalytically effective amount of a metal component selected from metals of the group VI and VIII, such as chromium, molybdenum, tungsten, iron, nickel, cobalt and platinum group metals, their compounds and mixtures thereof, which catalyst is deposited on χ-alumina obtained by drying and calcining alumina from boehmite with such a pore structure in which a total of at least 0,5 ml / g is constituted by pores of a size above 80 × 10 · ¹⁰ m (8 nm).

U.S. Pat. No. 3,630,888 discloses the treatment of hydrocarbon residues in the presence of a catalyst comprising a promoter selected from the group consisting of Group VIB and Group VIII elements, their oxides and combinations thereof, and a particulate catalyst consisting of silica, aluminum and combinations thereof with a total pore volume greater than 0.40 ml / / g, the pore volume comprising micropores and access channels, wherein the supply channels are spatially disposed in the gaps between the micropore structure, and one portion of the access channels having a diameter in the range from about 100 x 10 ^-10 m (10 nm) to about 1000 x 10 ^-10 m (100 nm), which portion includes 10 to 40 ° / pore volume, another portion of access channels having a diameter greater than 1000 x 10 " ¹⁰ m (100 nm), the portion comprising 10 to 40% of the pore volume, and finally remaining A portion of the pore volume consists of micropores having a diameter of less than 100 x 10 ^-10 m (10 nm), the remaining portion comprising 20 to 80% of the total pore volume.

U.S. Pat. No. 3,114,701 discloses - pointing out that in hydrofining processes, nitrogen compounds are removed from petroleum hydrocarbons in the presence of various catalysts, which generally include chromium and / or molybdenum oxides together with iron, cobalt and / or nickel oxides on porous an oxide carrier such as alumina or a mixture of silica and alumina - a hydrogenitrification process using a catalyst comprising a large concentra- tion of nickel and molybdenum on a carrier consisting predominantly of alumina for the treatment of hydrocarbon fractions boiling in the range of 82 ° C to about 566 ° C.

U.S. Pat. No. 2,843,552 discloses a catalyst containing a significant amount of chromium oxide together with alumina, which catalyst has very good abrasion and wear resistance, may contain molybdenum oxide deposited on a support by impregnation, and which can be used for reforming, desulfurization and isomerization of hydrocarbons.

U.S. Pat. No. 2,577,823 discloses the hydrogenation desulfurization of heavy hydrocarbon fractions containing 1% to 6.5 percent sulfur in the form of organic sulfur compounds such as reduced crude oil on a catalyst consisting of chromium oxides, molybdenum oxides and aluminum. obtained by simultaneous elimination of chromium oxides and molybdenum on a pre-formed slurry of alumina at a pH of between 6 and 8.

U.S. Pat. No. 3,265,615 discloses a process for preparing a supported catalyst, wherein a carrier having a large specific surface area, such as aluminum oxide, is impregnated with ammonium molybdenum and then introduced into an aqueous solution of chromium sulfate, and then the carrier is dried overnight. and then reduced with hydrogen at the following temperatures: 288 ° C, 399 ° C and 510 ° C, for 30 minutes each. The reduced material is sulfidated and used in the treatment of heavy or gas oil with a distillation range of 343 ° C to 499 ° C by Hydrofining.

U.S. Pat. No. 3,956,105 discloses a process for the hydrotreating of petroleum hydrocarbon fractions, such as residual fuel oils, using a catalyst comprising a Group VIB metal (chromium, molybdenum, tungsten), a Group VIII metal (nickel, cobalt), and Refractory inorganic oxide, which may be alumina, silica, zirconia, thorium oxide, boric oxide, chromium oxide, magnesium oxide and mixtures thereof The catalyst is obtained by dry mixing of a finely powdered Group VIB metal compound with a Group VIII metal compound and a refractory compound. inorganic oxide, peptizing the mixture and forming an extrudable pasty mass, extruding it and calcining it.

U.S. Pat. No. 3,640,817 discloses a two-step process for treating asphaltene-containing hydrocarbons. Each of the two catalysts used in the process comprises at least one metal component of the group consisting of molybdenum, tungsten, chromium, iron, cobalt, nickel, and platinum group metals, on a porous support such as alumina, silica, zirconia , magnesium oxide, titanium dioxide and mixtures thereof, with more than 50% of the volume of its macropores consisting of pores greater than 1000 χ 10 · ¹⁰ m (100 nmj) in the first catalyst and less than 50% of its macroporous pores content in the second catalyst Of a diameter exceeding 1000 xx 10 ¹⁰ m (100 nm).

U.S. Pat. No. 3,957,622 discloses a two-step process for the hydrogenation conversion of dark oils, respectively. black oils containing asphaltenes. In the first step, the feedstock is desulfurized on a catalyst in which less than 50% of its pore volume is formed by pores having a diameter greater than 1000 x 10 ^-10 m (100 nm). The accelerated conversion of the desulfurization of the asphaltenic fraction occurs in the second stage of the catalyst, in which more than 50% of its macropore volume is formed by pores with a diameter of more than 1000 x 10 ^-10 m (100 nm). Each of the two catalysts comprises at least one metal component of the group consisting of: of molybdenum, tungsten, chromium, iron, cobalt, nickel, platinum group metals and mixtures thereof, on a support such as aluminum oxide, silica, zirconium oxide, magnesium oxide, titanium dioxide, boron oxide, strontium oxide, or their hafnium oxide mixtures.

French patent specification 2 281 972 discloses the production of a catalyst comprising cobalt, molybdenum and / or nickel oxides on a support of aluminum oxide and 3 to 15% by weight of chromium oxide, and its use for refining hydrocarbon fractions, preferably for hydrogenation desulfurizing vacuum distillation fuel oils or residual atmospheric pressure distillate oils. The carrier can be obtained by co-precipitation of chromium and aluminum compounds.

U.S. Pat. No. 3,162,596 discloses that in an integrated process the residual hydrocarbon oil containing metallic impurities (nickel and vanadium) is first hydrogenated either with a hydrogen-providing substance as a diluent or on a catalyst containing at least one hydrogenation accelerating metal, deposited on alumina or silica as carrier, then vacuum distilled to separate the heavy metal oil fraction containing a lower amount of metal from the non-distilled residue, which boils at a temperature predominantly above 593 ^° C and contains an asphalt material. The heavy gas oil fraction is then catalytically cracked.

U.S. Pat. No. 3,180,820 discloses that it is possible to refine a heavy hydrocarbon feedstock by a hydrogenated desulfurization process carried out in two zones, each of which uses a solid hydrogenation catalyst comprising at least one metal of Groups VB, VIB and VIIIB of the Periodic Table of the Elements . Each of these catalysts may optionally be supported. In a preferred embodiment, the first zone comprises the unsupported catalyst slurry in oil and the second zone comprises the supported catalyst in a fixed bed, slurry, or fluidized bed. The supported catalyst support is a porous, refractory, inorganic oxide which may be alumina, silica, zirconia, magnesium oxide, titanium dioxide, thorium oxide, boron oxide, strontium oxide, hafnium oxide, oxides such as a complex of silica with alumina, silica with alumina, silica with zirconia, silica with magnesium oxide, alumina with titanium dioxide and silica with magnesium oxide. According to this patent, a supported catalyst suitable for use in the invention has a specific surface area in the range of about 50 m ² / g to 700 m ² / g, a pore diameter in the range of about 20 x 10 " ¹⁰ m (2 nm) to 600 xx 10 ^-10 m (60 nm) and a pore volume in the range of about 0.10 ml / g to 20 ml / g,

U.S. Patent Nos. 3,977,961 and 3,985,684 disclose methods for hydrogenating heavy crude oils and residues using one or two catalysts, one of which comprises a Group VIB metal and / or a Group VIII metal on a refractory inorganic oxide such as is alumina, silica, zirconia, magnesium oxide, boron oxide, phosphate, titanium dioxide, cerium oxide and thorium oxide, may contain IVA groups such as germanium, has a very high specific surface area and a very large pore volume,

For the first catalyst, at least about 20% of its total pore volume has an absolute diameter in the range of about 100 x 10 ^-10 m (10 nm) to about 200 x 10 ^-10 m (20 nm) when the catalyst has a particle diameter of up to 0.051 cm at least 15% of its total pore volume has an absolute diameter ranging from about 150 x 10 ^-10 m (15 nm) to about 250 x 10 ^-10 m (25 nm) when the catalyst has a particle diameter in the range of about 0.051 cm to ¹⁵ m about 0.102 cm, at least about 15% of its total pore volume has an absolute diameter ranging from about 175 x 10 ^-10 m (17.5 nm) to about 275 x 10 ^-10 m (27.5 nm) when the catalyst has a mean the particle diameter γ ranges from about 0.102 cm to about 0.32 cm, and the specific surface area ranges from about 200 m ² / g to about 600 m ² / g and the pore volume ranges from about 0.8 ml / g to about 3 0 ml / g. For the second catalyst, at least 55% of its total pore volume has an absolute diameter ranging from about 100 x 10 ^-10 m (10 nm) to about 200 x 10 ^-10 m (20 nmj, less than 10%) and has a pore volume diameter of pores below 50 x 10 ^-10 m (5 nm), less than about 25% of its total pore volume has a pore diameter above 300 x 10 ^-10 m (30 nm), with a specific surface area in the range of about 200 m ² / g to about 600 m ² / g and a pore volume in the range of about 0.6 ml / g to about 1.5 ml / g. These patents also disclose that the fraction obtained by the above-mentioned treatment can be further processed by catalytic cracking; hydrogenation cracking.

U.S. Pat. No. 4,054,508 discloses a process for removing metals and sulfur from residual ole fractions using two catalysts in three zones. In the first zone, the feedstock is contacted with the bulk of the first catalyst, which comprises a Group VIB metal and an iron group metal oxide, supported on alumina as a support, with at least 60% of its first pore volume consisting of pores ranging in diameter 100 x 10 10 ¹⁰ m (10 nm) to 200 x 10 ^j 10 m (20 nm) and at least about 5% / of its pore volume is thickened with pores greater than 500 x 10 ^{10 10} m (50 nm) in the second zone is then contacted with a second catalyst comprising a Group VIB metal and an iron oxide metal oxide on the alumina carrier, the second catalyst having a specific surface area of at least 100 m ² / g and at least 50% of its pore volume range from. .30 x 10 ^"(10 m 3 NMJ to 100 x 10" ¹⁰ m (10 nm), whereupon then in the third zone is contacted with a smaller proportion of the first catalyst.

We have now developed a process for the hydrotreating of heavy hydrocarbon containing metals, asphaltenes, nitrogen and sulfur compounds using a catalyst having special physical properties and comprising a hydrogenation component consisting of molybdenum and chromium and optionally cobalt.

Accordingly, the present invention provides a process for the hydrotreating of a heavy hydrocarbon fraction containing metals, asphaltenes, nitrogen and sulfur compounds to reduce the content of metals, asphaltenes, nitrogen compounds and sulfur compounds in the fraction by contacting the hydrogenation catalyst in the presence of hydrogen, and under conditions including a partial hydrogen pressure of 6.9 MPa to 20.7 MPa, an average catalyst bed temperature of 371 ° C to 438 ^° C, a throughput of 0.1 volume to 3 volumes of hydrocarbon fraction based on 1 hour and 1 catalyst volume, and an amount of recycled or added hydrogen in the range of 356 m ³ / m ³ to 2672 m ³ / m ³ , the method comprising using a hydrogenation catalyst containing a hydroge235073 feed component comprising molybdenum metal and chromium, their oxides, their sulphides or mixtures thereof into large pores m, catalytically active alumina, wherein molybdenum is present in an amount of 5 to 15% by weight, calculated as molybdenum oxide MoO _; based on the weight of hydrogenation catalyst, and chromium is present in an amount of 5 to 20%, calculated as chromium oxide Cr ₂ O ₃ and based on the weight of the catalyst, and wherein the hydrotreating catalyst has a pore volume of 0.4 cm ³ / g to 0.8 ^cm:! / g, specific surface in the range of 150 m ^? / g to 300 m ² / g, mean pore diameter in the range of 10 nm to 20 nm, and up to 10% of its pore volume consists of pores less than 5 nm in diameter, from 30% to 80 ° / its pore volume consists of pores with a diameter in the range of 5 nm to 10 nm, from 10% to 50% of its pore volume consisting of pores with a diameter in the range of 10 nm to 15 nm and up to 10% of its pore volume consisting of pores with a diameter greater than 15 nm.

The catalyst used in the hydrogenation process according to the invention may comprise a hydrogenation component which may additionally also contain cobalt metal or its oxide, its sulphide or a mixture thereof, with cobalt present in an amount of 0.1% to 5% by weight, calculated as oxygen cobalt CoO and based on the amount of hydrogenation catalyst by weight.

If the heavy hydrocarbon fraction to be treated contains metals in an amount which would adversely affect the action of the hydrogenation catalyst, it is preferable to first contact said heavy hydrocarbon fraction with the demetalate catalyst under demetalable conditions to reduce the metal content to a level which does not compromise of the catalyst.

The catalyst used in the process of the present invention for the hydrotreating of a heavy hydrocarbon fraction can be produced by calcining alumina in air at a temperature in the range of 427 ° C to about 760 ° C for 30 minutes to about 120 minutes to form the .alpha.-oxide. and subsequently impregnating the aluminum oxide with at least one aqueous solution containing thermally decomposable molybdenum and chromium salts, optionally also cobalt.

The attached drawing shows a simplified flow diagram of a preferred embodiment of the method according to the invention.

The present invention relates to a novel process for the hydrotreating of heavy hydrocarbon feedstocks. Such raw materials include asphaltenes, metals, nitrogen compounds and sulfur compounds. The feedstocks of the present invention are believed to contain a small amount of nickel and vanadium, for example, less than 40 ppm and more than 100 ppm nickel and vanadium (combined total nickel and vanadium) and up to about 25 weight percent asphaltenes. If the raw material contains either too large a total amount of nickel and vanadium or an extremely large amount of asphaltenes, the raw material can be subjected, as mentioned above, to a pretreatment to reduce the excess of said impurities. Such pretreatment includes a suitable hydrogenation treatment to remove metals from the feedstock and / or to convert the asphaltenes contained in the feedstock to reduce the amount of impurities to an acceptable content using any suitable, relatively inexpensive catalyst. The aforementioned impurities adversely affect the subsequent processing of such raw materials, unless their amount is reduced to acceptable sulfur.

Typical raw materials which can be satisfactorily processed by the process of the invention often contain a considerable amount of ingredients boiling above 538 ° C. Examples of typical raw materials are crude oils, topped crude oils, petroleum residues, atmospheric and vacuum distillation residues, heavy oil sands oils or heavy oil sands residues, and coal-derived hydrocarbon streams. Such hydrocarbon feedstocks contain organometallic impurities which have an adverse effect on the refining catalysts used in further processing. Metal impurities found in such raw materials include, but are not limited to, iron, vanadium, and nickel.

In most crude oils and residual reactions, nickel occurs as soluble organometallic compounds. The presence of nickel-porphyrin complex compounds and other organometallic nickel complex compounds causes serious difficulties in the refining process and in the upgrading of heavy hydrocarbon fractions, although the concentration of such complexes is relatively low. It is known that the cracking catalyst is rapidly destroyed and that its selectivity changes when operating in the presence of a noticeable amount of organometallic nickel compounds. A considerable amount of such organometallic nickel compounds in the feedstocks to be hydrotreated or hydrotreated causes considerable difficulties in these processes. The catalyst is deactivated and clogged or increased pressure drop in the fixed bed reactor due to the deposition of nickel compounds in the gaps between the catalyst particles.

The iron-containing compounds and the vanadium-containing compounds occur in virtually all crude oils and are accompanied by an asphaltic and / or asphaltenic fraction of a high Conradson carbon high crude oil. Of course, these metals accumulate in the bottom residue when the crude oil is boiled to remove such fractions which boil at a temperature below about 232 ° C to 316 ° C. If such a residue is treated by other processes, the presence of these metals adversely affects the catalyst, it being noted that the nickel-containing compounds adversely affect the cracking catalysts to a greater extent than the iron-containing compounds. When oils containing these metals are used as fuels in industrial furnaces, the metal surface of the furnaces is corroded.

While metallic impurities such as vanadium, nickel and gland often occur in small amounts in the various hydrocarbon fractions, they can also be present in concentrations higher than 40 to 50 ppm, or even higher than 1000 ppm. Of course, other metals are also present in a particular hydrocarbon stream. Such metals exist in the form of the oxide or sulfide of the metal in question, or in the form of a soluble salt of the metal in question or in the form of a high molecular weight organometallic compound, including naphthenates and porphyrins of metals and derivatives thereof. In any case, the raw material can be treated to remove metals before using the process of the invention if the total amount of nickel and vanadium is excessively large.

All values given above for the specific surface area are obtained by the nitrogen adsorption method BET. All pore volume values are obtained by the nitrogen adsorption method. All values reported for the mean pore diameter are calculated according to the formula where

APD mean diameter (X χ ΙΟ ^'10 m),

PV means pore volume (fcm ³ / g) a

SA means specific surface area (m ² / gj.

The pore size distribution is determined using a Digisorb 2500 nitrogen desorption method.

In the process of the invention, the catalyst is characterized by good metal removal efficiency, moderate desulfurization efficiency, and good deactivation stability when used at high temperature and / or at moderate pressure, e.g.

The hydrogenation component of the catalyst used in the process of the invention is a special component comprising molybdenum and chromium.

In one embodiment of the process of the invention, the hydrogenation component of the catalyst consists essentially of molybdenum and chromium, their oxides, their sulfides, or mixtures thereof. According to this embodiment, the invention provides a process for the hydrotreating of a hydrocarbon fraction comprising metals, asphaltenes, nitrogen compounds, and sulfur compounds to reduce the metal, asphaltenes, nitrogen, and sulfur compounds content of said fraction, said fraction being introduced under suitable conditions and conditions. The method is characterized in that a catalyst comprising a hydrogenation component consisting essentially of molybdenum metal and chromium, their oxides, their sulfides or mixtures thereof on large-porous, catalytically active alumina, wherein molybdenum is present, is used. in an amount of from about 5 wt% to about 15 wt%, calculated as molybdenum oxide MoO ₃ and based on the total weight of catalyst, chromium is present in an amount from about 5 wt% to about 20 wt%, calculated as oxide c Cr ₂ O ₃ and based on the total weight of catalyst, and the catalyst has a pore volume in the range of about 0.4 cm ³ / g to about 0.8 cm ³ / g, a specific surface area in the range of about 150 m ² / g up to about 300 m ² / g and a mean pore diameter ranging from about 100 x 10 ^-t ° m (10 nm) to about 200 χ 10 ¹⁰ m (20 nm).

The hydrogenation component of the catalyst used in the process of the invention may optionally also contain cobalt. Molybdenum and chromium and cobalt - if present - are present in the form of elements, oxides, sulphides or mixtures thereof. Molybdenum is present in an amount of from about 5% to about 15% by weight, calculated as molybdenum oxide MoO, based on the total weight of catalyst. The chromium is present in an amount of from about 5 wt% to about 20 wt%, calculated as Cr ₂ O ₃ and based on the total weight of catalyst. The cobalt, if present, is present in an amount of from 0.1% by weight to about 5% by weight, calculated as CoO and based on the total weight of catalyst.

Preferably, the molybdenum is present in an amount of from about 7 wt% to about 13 wt%, calculated as molybdenum oxide MoO 2 _; and based on the total weight of catalyst, chromium is present in an amount of from about 6 weight percent to about 15 weight percent, calculated as CrO _{2 .} and based on the total amount of catalyst, and cobalt is present in an amount of from about 1% to about 3% by weight, calculated as CoO and based on the total amount of catalyst.

Accordingly, the invention provides a method of hydrotreating a heavy hydrocarbon fraction comprising metals, asphaltenes, nitrogen compounds, and sulfur compounds to reduce the metal, asphaltenes, nitrogen, and sulfur compounds in said stream by contacting said fraction a catalyst under suitable conditions and in the presence of hydrogen, the method comprising the use of a catalyst comprising a hydrogenation component comprising molybdenum, chromium and cobalt, their oxides, their sulfides and mixtures thereof on large porous, catalytically active alumina, molybdenum present in an amount of from about 5 wt% to about 15 wt%, calculated as molybdenum oxide MoO _; and based on the total weight of catalyst, chromium is present in an amount from about 5 wt% to about 20 wt% o, calculated as chromium trioxide Cr _{2 O)} and based on the total weight of catalyst and the cobalt is present in an amount from about 0 wt% to about 5 weight ° / o, calculated as cobalt oxide CoO and based upon the total weight of the catalyst, and the catalyst has a pore volume in the range of about 0.4 cm -1 ^. / g to about 0.8 cm ³ / g, a specific surface in the range of about 150 m ² / g to about 300 m ² / g and a mean pore diameter in the range of about 100 χ 10 ¹⁰ meters (10 nm) to about 200 x 10 10 ¹⁰ m (20 nm).

The catalyst employed in the process of the invention employs suitable catalytically active large porous alumina. (Eg Aero 100 from American Cyanamid Companyj. Aluminum oxide should have a pore volume greater than 0.4 cm ³ / g, a specific surface area greater than 150 m ² / g, and a mean pore diameter greater than 100 x 10 " ^{, 0} meters (10 nm).

The catalyst mixture used in the process of the present invention can be conveniently prepared by impregnation of a suitable, catalytically active, large porous alumina with suitable metals. Such impregnation can be carried out with at least one solution of heat-degradable compounds of suitable metals.

The impregnation can be performed as a common impregnation when a single metal solution is used. Alternatively, the impregnation may be accomplished by sequential impregnation with individual metals from at least two solutions of heat-degradable compounds of suitable metals. The impregnated carrier is dried at a temperature of at least 121 ° C for at least 60 minutes, followed by annealing in air at a temperature of at least 538 ° C for at least 120 minutes. Preferably, the catalyst used in the process of the invention is obtained by first annealing the pseudobohmite in a stationary air at a temperature ranging from 427 ° C to about 760 ° C for 30 minutes to about 120 minutes to form χ-alumina . The aluminum oxide is then impregnated with an aqueous solution or solutions containing thermally decomposable salts of molybdenum and chromium and optionally cobalt.

The finished catalyst used in the process of the invention has a pore volume in the range of about 0.4 cm ³ / g to about 0.8 cm ³ / g, a specific surface area in the range of about 150 m ² / g to about 300 m ² / g and a mean pore diameter in the range of about 100 x 10 ^-10 m (10 nm) to about 200 x 10 ^-10 m (20 nm). Preferably, the catalyst has a pore volume in the range of about 0.5 cm ³ / g to about 0.7 cm ³ / g, a specific surface area in the range of about 150 m ² / g to about 250 m ² / g and a mean pore diameter in the range of about 110 x ^{10 -10} m (11 nm) to about 150 χ ¹⁰ m (15 nm).

In the catalyst used in the process of the invention, up to about 10% by volume of its pens should form pores with a diameter of less than 50 x 10 ^-10 m (5 nm), from about 30% to about 80% by volume of its pore volume. a diameter in the range of about 50 x 10 ^-10 m (5 nm) to about 100 x 10 ^-10 m (10 nm), about 10% to about 50% of its pore volume should form pores with a diameter in the range of 100 x 10 " ¹⁰ m (10 nm) to about 150 x 10" ¹⁰ m (15 nm) and up to 10% of its pore volume should form pores with a diameter greater than 150 x 10 " ¹⁰ m (15 nm).

The process according to the invention is particularly suitable for the hydrotreating of heavy hydrocarbon fractions, such as petroleum residues, atmospheric and vacuum distillation residues, heavy oils from oil sands, heavy oils from oil sands and liquid feedstocks obtained by coal processing. In addition, the process of the invention can be used to satisfactorily hydrotreat petroleum hydrocarbon distillates such as gas oils, recirculated fractions, e.g., for catalytic cracking, and fuel oils. If the amounts of nickel and vanadium are excessive, for example 100 to 150 ppm, or if the weight concentration of asphaltenes is too high, for example greater than 10%, the raw material should be subjected to a pretreatment to reduce the excess to an acceptable level before use for processing according to the method of the invention.

Working conditions for the hydrotreating of heavy hydrocarbon fractions, such as petroleum hydrocarbon residues and the like, include a hydrogen partial pressure ranging from 6.9 MPa to 20.7 MPa, an average catalyst bed temperature ranging from 371 degrees Celsius to about 438 ° C. C, an hourly volumetric rate ranging from about 0.1 volume of hydrocarbons per hour per catalyst volume to about 3 volumes of hydrocarbon per hour per catalyst volume, and an amount of recycled or added hydrogen in the range of about 356 m ³ / m ³ to about 2672 m ³ / / m ³ . Preferably, it is operated at a hydrogen partial pressure of from 8.27 MPa to 13.8 MPa, an average catalyst bed temperature of 388 degrees Celsius to 432 ° C, hourly volume velocities from 0.4 to 1 volume of hydrocarbons per hour per catalyst volume, and amount of recycled or added hydrogen from 890 m ³ / m ³ to 1780 m ³ / m ³ .

Using the process of the invention for treating hydrocarbon distillates, the operating conditions will be: partial hydrogen pressure from 1.4 MPa to 20.7 MPa, average catalyst bed temperature from 316 ° C to 427 ° C, hourly volume rate of 0.4 to 6 volumes of hydrocarbons per 1 hour per 1 catalyst volume and the amount of recycled or added hydrogen from 178 m ³ / m ³ to 1780 m ³ / m ³ , preferably a partial hydrogen pressure of 1.4 MPa to 8.27 MPa, an average catalyst bed temperature of 316 ° C to 399 ° C, hourly volumetric rate of 0.5 to 4 volumes of hydrocarbons per hour per catalyst volume, and amounts of recycled hydrogen or hydrogen added from 178 m ³ / m ³ to 1069 m ³ / / m ³ .

A preferred embodiment of the method of the invention is illustrated in the accompanying drawing, in which a simplified flow diagram is shown, but various auxiliary devices such as pumps, compressors, heat exchangers and valves are omitted. Since the necessity and location of use of such ancillary devices is readily determined by the skilled person, it is permissible to omit them because it facilitates the simplification of the drawing. This flow chart is intended to be illustrative only and does not limit the invention in any way.

Referring to the drawing, the vacuum distillation of light arabic hydrocarbon feedstock containing approximately 4 wt% sulfur, less than 0.5 wt% nitrogen and less than 100 ppm nickel and vanadium is fed from reservoir 10 via line 11 through a pump 12 to line 13. A stream of hydrogen-containing recycle gas, which will be described in greater detail below, is also fed to line 13 and is mixed with a hydrocarbon feed to form a mixed gas comprising hydrogen and hydrocarbons. This mixed stream containing hydrogen and hydrocarbons is then fed via line 13 to the furnace 15 where it is heated to a temperature of 404 ° C to 416 ° C. The heated stream is then discharged via line 16 to the reaction zone 17.

Reaction wall 17 comprises one or more reactors, each containing at least one fixed catalyst bed. The catalyst comprises a hydrogenation component which contains about 5 wt% to 15 wt% molybdenum, calculated as molybdenum oxide MoO 2 _, and based on the total amount of catalyst, 5 wt% to 20 wt% chromium, calculated as chromium trioxide Cr ₂ O: ia based on the total weight of catalyst, on the large porous, catalytically active alumina.

Molybdenum and chromium are both in the form of elements or as oxides, as sulfides or as mixtures thereof. The catalyst has a pore volume in the range of about 0.4 cm ³ / g to about 0.8 cm ³ / g, a specific surface area in the range of about 150 m ² / g to about 300 m ² / g, a mean pore diameter in the range of about 100 x 10 ^-10 m (10 NMJ to about 200 χ 10 ~ ^1θ m (20 nm) and a distribution of pore sizes in which up to about 10% of the total pore volume is in pores of diameter in the range up to about 50 x 10 ~ ^J Å (5 nm), about 30% to about 80% of the pore volume is in pores of diameter from about 50 χ 10_ ¹⁰ m (5 NMJ to about 100 x 10 ^{_1 ()} m (10 nm), about 10 to about 50 % of the volume is provided by pores of diameter in the range of about 100 x χ 10 'm (10 nm] to 150 x 10 ~ ^J0 m (15 NMJ, and up to about 10% of the pore volume is in pores of diameter greater than 150 x 10 ^{_J. 1} m (15 nm).

The operating conditions used in the process depicted in the above scheme include a partial hydrogen pressure in the range of about 8.27 MPa to about 11.0 MPa, an average catalyst bed temperature in the range of about 404 ° C to about 416 ° C, hourly volume rate from about 0.4 hydrocarbon volume per hour per catalyst volume to about 0.8 hydrocarbon volume per hour per catalyst volume, and an amount of recycled hydrogen in the range of about 890 m ³ / m ³ to about 1425 m ³ / m ³ .

The stream exiting from the reaction zone 17 is passed through line 18 to a high temperature (high pressure) gas / liquid separator 19 maintaining the same pressure as in the reactor and a temperature in the range of about 404 ° C to about 416 ° C. In the separator 19, the hydrogen-containing gas is separated from the other portions of the stream leaving the reaction zone 19. The hydrogen-containing gas is removed from the separator 19 via line 20. After cooling, it is fed to a light hydrocarbon separator 21 in which light hydrocarbons condense. The hydrogen-containing gas is discharged via line 23 to a scrubber 24, in which the hydrogen sulphide is removed from the system by scrubbing and discharged from the system via line 25. The hydrogen-containing gas to be scrubbed is passed through line 14, to which, if necessary, hydrogen is supplied via line 26. The hydrogen-containing gas stream is then added to the hydrocarbon feedstock in the line

13, as already mentioned.

The liquid fractions are withdrawn from the high-temperature (high-pressure) gas fraction separator 19 from the liquid fractions via line 27 into the high-temperature expansion chamber (drum) 28. Here, their pressure is reduced to atmospheric pressure; their temperature ranges from about 371 degrees Celsius to about 427 ° C. In the expansion chamber 28, light hydrocarbons, which include not only naphtha, but also distillates which boil up to a temperature in the range of about 288 ° C to 316 ° C, such as fuel oils, are separated from the rest of the product and removed from the system. The light hydrocarbons containing 1% to 4% by weight of hydrocarbons having 4 carbon atoms, 2 to 5% by weight of naphtha (5-carbon to hydrocarbons boiling at 182 ° C) and 10 to 15% by weight. Hydrocarbons having a distillation range of 182 degrees Celsius to 343 ° C, based on the carbon 235073 hydrogen feedstock, can be separated into individual fractions and discharged to reservoirs or other processing equipment.

The heavier fractions remaining after separation of the light hydrocarbons, i.e. the boiling point at 316 degrees Celsius, in the range of 60 to 90% by weight, based on the hydrocarbon feedstock, are withdrawn from the expansion chamber 28 via line 30 for use as feedstocks. other processes or as a low sulfur heavy industrial fuel. Such liquid fractions contain about 0.6 to 1.2 wt% sulfur, about 1.0 to 3.0 wt% asphaltenes, and 5 to 15 ppm nickel and vanadium. In addition, more than 50% of the material boiling above 538 ° C is converted to a material boiling below 538 ° C.

The liquid fractions are passed through line 31 to an oven 32 or other suitable heating device where it is heated to a temperature of up to 427 ° C.

The heated stream from the furnace 32 is passed through a line 33 to a vacuum column 34 in which vacuum gas oil is separated from the low sulfur fuel residue. The vacuum gas oil is removed from the vacuum column 34 via line 33 to a reservoir or to a conventional catalytic cracker (not shown). The low sulfur fuel residue is removed from the vacuum column 34 via line 38 to a storage tank or other production units where it can be used as an energy source.

Alternatively, material boiling above 316 ° C, which is withdrawn from the expansion chamber 28 via line 30, may be passed through line 37 to a catalytic cracker for cracking residual fractions (not shown).

The following examples illustrate the invention.

Example 1

A catalyst, hereinafter referred to as Catalyst A, containing 8.3 wt.% Of molybdenum oxide MoO ₃ and 8.3 wt.% Of Cr ₂ O ₃ based on the total weight of catalyst on large porous catalytically active alumina was produced. . 40.8 g of aluminum oxide (Aero-100, American Cyanamid Company) were impregnated with a solution of ammonium dichromate and ammonium molybdate. The alumina used has a grain size ranging from 0.83 millimeters to 1.17 mm and has been annealed in air for 2 hours at a temperature of about 649 ° C.

The solution used for impregnation is obtained by dissolving 6.8 g of ammonium dichromate and 5.3 g of ammonium molybdate in 40 ml of distilled water.

The impregnated alumina is dried under a heat emitter in stationary air overnight to remove excess water. The dried material was then calcined at 538 degrees Celsius for 2 hours in stationary air. The finished catalyst, referred to as Catalyst A, is shown in Tab. I is one embodiment of a catalyst used in the process of the invention.

Example 2

A commercially available catalyst is used for comparison. This commercial catalyst (HDS-2A) contains 3% by weight of CoO and 13% by weight of molybdenum MoO ₃ on alumina as carrier and is hereinafter referred to as Catalyst B.

Example 3

For comparison, another hydrogenation catalyst (Nalco Chemical Company) was used. It is hereinafter referred to as Catalyst C and contains 3 wt% cobalt oxide and 13 wt% molybdenum oxide MoO ₃ on alumina as carrier. The properties of Catalysts A, B and C are shown in Table I, which also lists the physical properties of the alumina used as support for Catalyst A. This catalyst support is designated as Catalyst D in Table I. The introduction of metals into alumina does not appreciably affect the size distribution pore volume, pore volume, specific surface area or mean pore diameter of the alumina.

Table I

Properties of catalysts

Catalyst AND (B) C D hydrogenation components weight% CoO 3 3 Cr ₂ O ₃ 8.3 - - - MoO ₃ 8.3 13 13 - physical properties specific surface area, m ² / g 208 330 284 222 pore volume, cm ³ / g mean pore diameter, 0.60 0.61 0.61 0.73 X x 10- ¹⁰ m, 116 73 86 131 nm 11.6 7.3 8.6 13.1 percent of the total pore volume represented by the pores 0 average from 0 to 50 χ 10 ^-10 m (0 to 5 nm) from 50 to 100 x 10 ~ ¹⁰ m 6.3 26.7 14.2 1.4 (5 to 10 nm) from 100 to 150 x 10- »m 69.5 58.8 76.3 56.7 (10-15 nm), from 150 to 200 x 10- ¹⁰ m 23.1 4.3 2.1 36.6 (15-20 nm) from 200 to 300 x 10 ^-10 m 0.4 1.6 0.7 1.6 (20 to 30 nm) from 300 to 400 x 10-m 0.3 2.1 1.1 1.4 (30 to 40 nm) above 400 χ 10 ~ ¹⁰ m 0.1 0.8 0.8 0.4 (above 40 nm) 0.3 5.7 4.8 1.9 Continuation of Table I Catalyst E F G hydrogenation components,% by weight CoO Cr ₂ O _{; i} - 5.2 15.4 M0O3 9 8.6 7.7 physical properties specific surface area, m ² / g 201 197 198 pore volume, cm ³ / g 0.66 0.60 0.59 mean pore diameter, X x 10 ^-1 ° m 130 122 119 mean pore diameter, nm 13.0 12.3 11.9 percent of the total pore volume represented by the pores 0 average from 0 to 50 x 10 ¹⁰ m (0 to 5 nm) from 50 to 100 x 10 ~ «> m 3.1 2.2 2.7 (5 to 10 nm) 68.0 64.8 65.8

235673

Continuation of Table I

Catalyst from 100 to 150 x 10 ¹⁰ m (10 to 15 nm) from 150 to 200 x 10 ¹⁰ m (15 to 20 nm) from 200 to 300 x 10 ¹⁰ m (20 to 30 nm) from 300 to 400 x 10 ¹⁰ m (30 to 40 nm) above 400 x 10 ¹⁰ m (above 40 nm)

Example 4

To determine the effect of varying concentrations of chromium trioxide on a catalyst containing approximately 9% by weight molybdenum trioxide on alumina (Aero 100) as carrier, three additional catalysts were prepared as described in Example 1. However, only the amounts of metals used were reaches the desired compositions of the finished catalysts. These three catalysts are hereinafter referred to as E, F, G catalysts and are manufactured using the same type of aluminum oxide (Aero 100) used in the production of Catalyst A. Their chemical composition and physical properties are also shown in Table I above. Again, the table shows that the deposition of metals on alumina does not appreciably affect the physical properties of alumina.

Example 1 a d 5

Each of the catalysts described above is determined to be suitable for treating the vacuum residue of the light Arabic hydrocarbon feedstock. The relevant properties of this raw material are given in Table II.

Table II

Raw material properties carbon, wt% 84.91 hydrogen, wt% 10.61 atomic H / C ratio 1.499 nitrogen, wt% 0.34 sulfur, wt% 4.07 nickel, ppm 17.5 vanadium 51.1 boiling fraction to 538 ° C 13.6 carbon Ramsbottom, weight why. 15.2 heavy fractions, ° API 8.8 density at 15 ° C, g / cm ³ 1.0080 asphaltenes, wt% 8.0 high molecular weight alkane-cyclanic fraction wt% 39.2 resin, wt% 52, 8 resin / asphaltenes ratio 6.6

E F G 27.8 30.6 30.2 0.2 0.8 0.2 0.3 0.7 0.3 0.1 0.2 0.1 0.5 0.6 0.5

Each test is performed on a test device with automatic control of pressure, amount of reagents and temperature. The reactor consists of a thick-walled stainless steel tube with an internal diameter of 0.95 cm. The outer diameter of the heat pipe is drawn upward through the center of the reactor. The reactor is heated by an electrically heated steel block. The hydrocarbon feed is fed to the reactor by a Russia pump, which is a positive displacement pump. The catalyst material having a particle size in the range of 0.83 to 1.17 mm is deposited on the refractory alumina particles having a particle size in the range of 2.00 to 2.38 mm. Approximately 20 cm ^{3 of} catalyst catalyst bed are used in each test. This amount of catalyst will form a catalyst bed column having a length in the range of about 25.4 cm to about 30.5 centimeters.

For each test, a 25 cm high alumina layer having a particle size in the range of 2.00 to 2.38 mm was introduced above the catalyst bed. The catalyst to be used in the test is introduced into the annular space between the heat pipe and the inner wall of the reactor having an internal diameter of 0.95 cm.

Prior to use, each of the catalysts was annealed in stationary air at about 538 ° C for 1 hour. It is then allowed to cool in a desiccator and charged to the appropriate reactor.

The catalyst is then subjected to the pretreatment described below. The reactor was charged to a reactor block at 149 ° C. A gaseous mixture containing 8 mol% hydrogen sulfide in hydrogen at a rate of 28.3 liters / h at a pressure of 3.5 MPa and at a temperature of about 149 ° C was started with the catalyst. After 10 to 15 minutes of gas flow through the catalyst, the block temperature was raised to 204 degrees Celsius. After at least one additional hour, and when at least 28.3 liters of gaseous mixture has passed through the system, the block temperature is raised to 371 ° C. Thereafter, the gaseous mixture is continued through the catalyst bed for at least another hour in an amount of at least 28.3 liters. Thereafter, the gas mixture was cut off, hydrogen was introduced into the reactor at a pressure of 20 psig, the flow rate was adjusted to 17 liters / hour, and the temperature was increased to

235373, the average catalyst bed temperature was 404 ° C. The hydrocarbon feedstock is then introduced at a rate such that an hourly volumetric rate of 0.59 volumes of hydrocarbons per 1 ppm per catalyst volume is achieved.

From the stream leaving the reaction zone, the liquid fraction is collected in the liquid collecting vessel, while the gaseous fractions pass through the collecting vessel and are routed through a pressure regulating valve and a moisture meter to the outlet port.

After 1 to 3 days, the average temperature of the catalyst bed was increased to 416 ° C. After a longer period of time, for example about 3 to 5 days, the temperature of the catalyst bed is raised to about 427 ° C.

Samples collected in the collection vessel are analyzed. The results obtained in the tests are shown in Table III. These data are obtained from samples taken during the fifth to ninth day of the test run at an hourly volumetric rate of 0.59 hydrocarbon volume per hour per catalyst volume, at 427 ° C and 8.37 MPa if not otherwise stated.

Table III

Test results

Handle no. 1 2 3 4 catalyst AND (B) C E temperature, ° C 427 427 416 416 pressure, MPa 8.37 8.37 8.37 8.37 hourly volume velocity 0.59 0.59 0.59 0.59 % sulfur removal 65.4 77.4 85 59 % nickel removal 85 43 48 40 % vanadium removal 92.5 94.9 57 79 % conversion of asphaltenes 70 68.8 54 67.5 liquid fraction density, ° API 20.1 19.9 20.4 17.5 density at 15 ° C, g / cm ³ 0.9328 0.9341 0.9310 0.9491 % conversion of shares boiling above 538 ° C in boiling fractions below 538 ° C 59.1 47.3 40 - number of days in operation 6 7 7—18 * ’ 5

* ’Combined sample from the 7th to 18th day

Table III (continued)

Test results

Handle no. 4 5 6 catalyst E F G temperature, ° C 427 427 427 pressure, MPa 8.37 8.37 8.37 hourly volume velocity 0.59 0.59 0.59 % sulfur removal 60.5 60 69.6 % nickel removal 64 64 78 % vanadium removal 81 87 90.6 % conversion of asphaltenes 66 70 71 liquid fraction density, ° API 19.3 17.6 21.1 density at 15 ° C, g / cm ³ 0.9378 0.9485 0.9267 % conversion of shares boiling above 538 ° C in aliquots boiling below 538 ° C 53 60.6 58.6 number of days in operation 9 10 7

The results shown in Table III show that the batch using catalyst A, i.e. treated by one embodiment of the process of the invention, is superior to the tests using the other catalysts. As the results show, better nickel removal, about the same vanadium removal, better conversion of asphaltenes, better conversion of boilers above 538 [deg.] C., but less sulfur removal than the other catalysts are achieved by the process of the invention. Therefore, the process according to the invention is a suitable process for the removal of metals and sulfur, for the conversion of asphaltenes and for the conversion of fractions boiling above 538 [deg.] C. if a heavy hydrocarbon stream is to be treated. In addition, data relating to feedstocks 1, 4, 5 and 6 show that the presence of chromium trioxide Cr ₂ O,> in the catalyst results in better removal of metals, sulfur, higher conversion of asphaltenes and fractions boiling above 538 ° C at boiling points below 538 degrees Celsius.

Example 6

The catalyst, hereinafter referred to as catalyst H, is prepared with a content of 1.1% by weight of cobalt oxide CoO, 8.2% by weight of molybdenum oxide MoO ₃ and 8.2% by weight of chromium trioxide Cr ₂ O ₃ , based on the total weight amount of catalyst, on large porous, catalytically active alumina. 63.8 g of this alumina (Aero 100, American Cyanamld Company) were treated with a solution containing ammonium dichromate and ammonium molybdate. This alumina has a grain size in the range of 0.83 to 1.17 mm and was previously annealed in air at 649 degrees Celsius for 2 hours.

The solution used for impregnation is obtained by dissolving 10.6 g of ammonium dichromate and 8.3 g of ammonium molybdate in 80 ml of distilled water. The alumina to be impregnated is added to this solution and the resulting mixture is allowed to stand overnight.

The soaked alumina is then dried under a heat emitter in stationary air for approximately 2 hours to remove excess water. The dried material is then calcined at 538 ° C for 2 hours in stationary air.

Half of the annealed material is impregnated with a solution of cobalt nitrate hexahydrate. This solution is prepared by dissolving 1,2 g of cobalt nitrate hexahydrate Co (NO ₃ ) ₂ - 6 H ₂ O in 40 ml distilled water. The mixture of calcined material and this solution was allowed to stand overnight.

The material is then dried in the stationary air for approximately 2 hours under a heat emitter. The dried material is then calcined in immobilized air at 538 ^° C for 2 hours. The finished catalyst, i.e. catalyst H, represents a preferred embodiment of the catalyst used in the process of the invention. Its properties are given in Table IV.

Example IV

Another catalyst, hereinafter referred to as Catalyst I, is prepared with a content of 3.1% by weight of cobalt oxide CoO, 8.1% by weight of molybdenum oxide MoO ₃ and 8.1% by weight of chromium trioxide Cr ₂ O ₃ based on the total weight amount of catalyst, supported on alumina (Aero 100). This catalyst was prepared as described in Example 6, but using the appropriate amounts of metals to achieve the desired composition. This catalyst, i.e. catalyst I, represents another embodiment of the catalyst used in the process of the invention. Its properties are also given in Table IV.

Table IV

Test results

Catalyst H AND hydrogenation components,% by weight CoO 1.1 3.1 Cr ₂ O _{; 1} 8.2 8.1 MoO.j 8.2 8.1 physical properties specific surface area, m ² / g 176 186 pore volume, cm ³ / g mean pore diameter, 0.55 0.56 X 10- ¹⁰ m 125 120 the percentage of pore volume having a diameter in the range to 50 x 10 ^_, Å (5 nm) from 50 to 100 x 10 ¹⁰ m 3.9 4.7 (5 to 10 mn) from 100 to 150 χ ΙΟ “ ¹⁰ m 66.3 65.4 (10 nm to 15 nm) from 150 to 200 x 10 ^-10 m 28.9 29.1 (15 to 20 nm) from 200 to 300 x 10 ^-10 m 0.3 0.3 (20 to 30 nm) from 300 to 400 x 10 - < ⁰ m 0.3 0.3 (30 to 40 nm) from 400 to 600 χ 10 ~ ^ω m 0.1 0.1 (40 to 60 nm) 0.2 0.1

Example 8

Tests are conducted with Catalyst H and Catalyst I to determine their suitability for converting the vacuum residue of the light Arabic hydrocarbon feedstock described in Table II above.

Each of these tests was carried out as described in Example 5.

The results of these tests are shown in Table V, which also shows the test results with Sticks No. 1, 2 and 3 described in Table III.

Table V

Test results

Handle no. 7 8 catalyst H AND Operating conditions temperature, ° C 427 427 overpressure, MPa 8.37 8.37 hourly volume velocity, obj./obj./h 0.59 0.59 pattern of 9 9 % sulfur removal 75 83 % nickel removal 79 73 % vanadium removal 93 86 % conversion of asphaltenes 79 75 % conversion of temperature components boiling above 538 ° C in the component boiling point below 538 ° C 66 50 density of liquid fractions, ° API 20.9 20.7 density at 15 ° C, g / cm ³ 0.9280 0.9292

3 5 O 7 4

Continuation of Table

Handle no. 1 2 3 catalyst AND (B) C Operating conditions temperature, ° C 427 427 416 overpressure, MPa 8.37 8.37 8.37 hourly volume velocity (obj./obj./h) 0.59 0.59 0.59 pattern of 6 7 7—18 * ¹ % sulfur removal 65 77 85 % nickel removal 85 43 48 % vanadium removal 93 95 57 % conversion of asphaltenes 70 69 54 % conversion of temperature components boiling above 538 ° C in the component boiling point below 538 ° C 59 47 40 density of liquid fractions, ° API 20.1 19.9 20.4 density at 15 ° C, g / cm ³ 0.9328 0.9341 0.9310 * ’Combined sample of material obtained from 7 April. by day 18

These results show that the process of batch # 7, which is a preferred embodiment of the process of the invention using the preferred form of catalyst used in the process of the invention, always results in better results compared to the other feeds tested. It achieves good desulfurization, good nickel removal, good vanadium removal, higher conversion of asphaltenes and higher conversion of components boiling above 538 ° C to a boiling point below 538 ° C.

In processing No. 8 of a further embodiment of the process according to the invention, a catalyst is used which contains a greater amount of cobalt (3.1 wt% CoO) than a catalyst H (1.1 wt% CoO) but this amount still falls within a wide range of 0, 1% to 5% by weight of cobalt oxide as mentioned above for the catalyst used in the process of the invention. An increased amount of cobalt improves desulfurization efficiency, somewhat decreases the amount of removed metals, the conversion of asphaltenes and the conversion of components boiling above 538 ° C to the boiling component below 538 ° C.

When processing No. 1 handle,

Claims (3)

Process for the hydrotreating of a heavy hydrocarbon fraction containing metals, asphaltenes, nitrogen compounds and sulfur compounds to reduce the content of metals, asphaltenes, nitrogen compounds and sulfur compounds in this fraction to produce a hydrotreated product suitable, for example, for subsequent cracking to obtain gasoline and distillates wherein the fraction is contacted with a hydrogenation catalyst in a catalyst which contains chromium and molybdenum in its hydrogenation component, but not cobalt. The absence of cobalt leads to lower desulphurisation, slightly improved metal removal, lower conversion of asphaltenes and lower conversion of components boiling above 538 ° C to components boiling below 538 ° C. The processing of batches 2 and 3 represents comparative experiments using prior art catalysts. The treatment of these feedstocks achieves substantially the same degree of desulfurization as the process of the present invention, but less metal removal, less conversion of asphaltenes and less conversion of components boiling above 538 ° C into a component boiling below 538 ° C. In view of the above, the process of the invention is a novel process for the hydrotreating of heavy hydrocarbon streams. The use of less cobalt in the catalyst together with Group VIB metals of the Periodic Table, ie chromium and molybdenum, unexpectedly results in this process using such a catalyst becoming a very efficient process for treating such heavy hydrocarbons. OF THE INVENTION hydrogen present and under conditions including a partial hydrogen pressure of 6.9 MPa to 20.7 MPa, an average catalyst bed temperature of 371 ° C to 438 degrees C, a throughput of 0.1 volume to 3 volumes of hydrocarbon fraction, based on 1 hour and 1 catalyst volume, and the amount of recycled or added hydrogen in an amount of 356 m ³ / m ³ to 2672 m ³ / m ³ , characterized in that a hydroge233073 hydrogenation catalyst containing molybdenum metal is used and chromium, their oxides, their sulphides or a mixture of these on large porous, catalytically active alumina, where molybdenum is present in an amount of 5 to 15% by mass, calculated as molybdenum oxide MoO _; and based on the mass of hydrogenation catalyst, and chromium is present in an amount of 5 to 20% by weight, calculated as Cr trioxide ₂ O ₃ and based on the weight of the catalyst, and wherein the hydrotreating catalyst has a pore volume of 0.4 cm ³ / g to 0.8 cm ³ / g, a specific surface area of 150 m ² / g to 300 m ² / g a mean pore diameter in the range of 10 nm to 20 nm, and up to 10% of its pore volume consists of pores with a diameter of less than 5 nm, from 30% to 80% of its pore volume consists of pores with a diameter of 5 nm to 10 nm, 10% to 50% of its pore volume consists of pores with a diameter of 10 nm to 15 nm and up to 10% of its pore volume consists of pores with a diameter greater than 15 nm. 2. A process according to claim 1, further comprising the use of a hydrogenation catalyst, the hydrogenation component of which also contains cobalt metal or its oxide, its sulphide or a mixture thereof, wherein the cobalt is present in an amount of 0.1% to 5% by weight. calculated as CoO and based on the weight of the hydrogenation catalyst. 3. The process of item 1 or 2, wherein said heavy hydrocarbon fraction comprises metals in an amount that would adversely affect the action of the hydrogenation catalyst, wherein said heavy hydrocarbon fraction is first contacted with a demetalate catalyst under demetalate conditions for reducing the metal content to a level which does not compromise the action of the hydrogenation catalyst.